39f8dc43b7
Now that u[ret]probes can use name-based specification, it makes
sense to add support for auto-attach based on SEC() definition.
The format proposed is
SEC("u[ret]probe/binary:[raw_offset|[function_name[+offset]]")
For example, to trace malloc() in libc:
SEC("uprobe/libc.so.6:malloc")
...or to trace function foo2 in /usr/bin/foo:
SEC("uprobe//usr/bin/foo:foo2")
Auto-attach is done for all tasks (pid -1). prog can be an absolute
path or simply a program/library name; in the latter case, we use
PATH/LD_LIBRARY_PATH to resolve the full path, falling back to
standard locations (/usr/bin:/usr/sbin or /usr/lib64:/usr/lib) if
the file is not found via environment-variable specified locations.
Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/1648654000-21758-4-git-send-email-alan.maguire@oracle.com
36 lines
828 B
C
36 lines
828 B
C
// SPDX-License-Identifier: GPL-2.0
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#include "vmlinux.h"
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#include <bpf/bpf_helpers.h>
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#include <bpf/bpf_tracing.h>
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#define PT_REGS_SIZE sizeof(struct pt_regs)
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/*
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* The kernel struct pt_regs isn't exported in its entirety to userspace.
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* Pass it as an array to task_pt_regs.c
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*/
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char current_regs[PT_REGS_SIZE] = {};
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char ctx_regs[PT_REGS_SIZE] = {};
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int uprobe_res = 0;
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SEC("uprobe")
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int handle_uprobe(struct pt_regs *ctx)
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{
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struct task_struct *current;
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struct pt_regs *regs;
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current = bpf_get_current_task_btf();
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regs = (struct pt_regs *) bpf_task_pt_regs(current);
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if (bpf_probe_read_kernel(current_regs, PT_REGS_SIZE, regs))
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return 0;
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if (bpf_probe_read_kernel(ctx_regs, PT_REGS_SIZE, ctx))
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return 0;
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/* Prove that uprobe was run */
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uprobe_res = 1;
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return 0;
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}
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char _license[] SEC("license") = "GPL";
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